How to make a "reflective tape" material in cycles?
Such a material works by reflecting the incoming light back towards the direction it originated - since your car headlights are very close to your own line of sight, you see a strong reflection of your own lights. You can replicate this behaviour in a material by simply manipulating the surface Normal in a Glossy shader that can then be mixed into any other shaders on the material - as shown :



The key here is to connect the Geometry Incoming socket to the Normal of the Glossy shader so that any reflections occur back towards the source. You can manipulate the Roughness to control how sharp the reflection is (ie, roughness of zero would reflect all light direct back to the source but a slight roughness will spread it out, to allow it to be visible (but fainter) at wider viewing angles) - and so how close to the light souce line of sight the viewer must be to allow them to see its reflection.

Any light source close to the line of sight of the camera will now strongly reflect back and make the material appear to 'glow' with respect to other (non-reflective) materials. You can vary the Color of the Glossy node to affect the color of the reflection.

Example showing one reflective cube and one 'normal' cube :